Study The Space-time Change On Thawing Plate In Cold Regions Tunnel

Along with the transfer of the west development strategy and the need ofeconomic development,more and more cold and highway tunnel construction.But the permafrost regions of the influence ofclimate, geological condition, construction technology, under construction or already running tunnelappeared different degree of freezing injury. The main reason lies in the cold and the building of theoriginal rock of the tunnel of the thermal equilibriumcondition had great changes, melting plate holecaused the temperature environment inside and outside the tunnel in time and space and seasonalvariation of the bearing capacity of surrounding rock strength so that the tunnel repeatedly sufferfrom seasonal frost heave effectlead to diseases.In this paper, the method of using numerical simulation research is mainly focused on thetunnel in different construction and operation stages thawing plate to change the size of the tunneland the tunnel support structure mechanics characteristic. This study considers the unstabletemperature field with phase change, the different construction stages and characteristics of thetunnel after the hole inside and outside temperature distribution, tunnel the laid of heat preservationand heat insulation layer, thawing plate evolution mechanism factors, factors such as different levelof surrounding rock, analysis of tunnel are summarized to thawing plate changes over time and thesize of the displacement of retaining structure and cold regions tunnel stress are studied.According to the actual tunnel construction in different stages of the excavation and the hole ofthe complexity of the internal and external temperature distribution, this paper, by using generalfinite element software on numerical simulation research mainly divided into two parts: the part oftunnel excavation is divided into rare hole stage, early stage, two line and well versed in operationstage, considering material with phase change the duration of exposure and the unsteady caseconstruction hole inside and outside temperature distribution differences of the trend analysis oftunnel melting plate; Others is consider freezing and frozen rock mass physical material parametersin the changes in temperature change of season, comparative analysis of different grade and differentthawing plate range of surrounding rock under the influence of the depth, emphatically analyzed thelining of tunnel surrounding rock stress deformation law of supporting structure, and comparison inorder to will be a rough quantitative influence degree.Through the comparison and analysis of the calculation results: tunnel thawing plate of seasonalchange the hole inside and outside temperature had a greater influence on the environment. Tunnelmelting plate with hole temperature range is increasing but the increase rate decreases gradually; Different construction stages of different thawing plate influence on tunnel, which has distinctconstruction heat source; The laid of thermal insulation materials can effectively avoid the tunnel ofthe seasonal freezing and thawing of melting. Decreases as the tunnel melting plate depth of tunnelsupporting structure stress, displacement and plastic strain increases, indicates that tunnel meltingplate plays an significant role in stability of tunnel structure, and with the increase of the grade ofsurrounding rock, the stress of the tunnel support structure more adverse, inverted arch and arch footposition is easy to be destroyed first. So the construction of the tunnel arch foot of a certain intensitystrengthening measures should be taken.